This invention relates to a rotary internal combustion engine. The engine includes an engine housing, and at least one rotor mounted for rotation within the housing. The rotor is adapted for rotation about an axis and includes at least one generally U-shaped flow conduit cooperating with an air/fuel mixture and spark plug to effect combustion and power delivery to the rotor. The operation of the rotor in the present engine provides a more efficient and less costly alternative to conventional gas turbine engines.
In internal combustion engine markets below 1000 hp, conventional gas turbine engines are not competitive with piston engines (Diesel and Otto cycle) because of either engine cost or fuel efficiency. Gas turbine engines have compressors and power sections that are composed of stages, each stage having a moving element (rotor, impeller) and a stationary element (stator, nozzle, diffuser). These stages individually have a limited pressure capability. Current stage designs also have aerodynamic losses of several types, leakage losses and compressor surge problems. Therefore, the high combustion chamber pressures needed for good engine efficiency require multiple stages, which drives up engine cost. Recuperators or regenerators may be added to low pressure gas turbine engines to improve efficiency, but these devices also have a cost penalty.
The engine of the present invention is similar in many ways to conventional gas turbine engines, but has a compressor which can produce high ( e.g. 170 psig) combustion chamber pressure in a single stage. There is no diffuser in the compressor, so surge is not possible. Compressor and power section efficiencies are nearly 100%. The power section is capable of dealing with this high pressure ratio with fewer stages. This invention has more torque at low engine speeds than conventional gas turbine engines. These attributes make the present engine competitive in cost and performance to piston engines.
Therefore, it is an object of the invention to provide an internal combustion engine which resembles a conventional gas turbine engine, but is competitive in both cost and performance to piston engines.
It is another object of the invention to provide an internal combustion engine which can produce high combustion chamber pressure in a single stage.
It is another object of the invention to provide an internal combustion engine which eliminates the possibility of surge by removing the diffuser in the compressor.
It is another object of the invention to provide an internal combustion engine which includes nearly 100% compressor and power section efficiencies.
It is another object of the invention to provide an internal combustion engine which has more torque at low engine speeds than conventional gas turbine engines.
It is another object of the invention to provide an internal combustion engine which achieves a total engine efficiency of around 35%.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a rotary internal combustion engine. The engine includes a housing within which is mounted for rotation at least one rotor. The rotor is configured for rotation about an axis and includes at least one flow conduit. The flow conduit includes a compression region having an inlet proximate to the rotation axis of the rotor and extending radially towards a periphery of the rotor. A mixture of air and fuel enters the flow conduit through the inlet and travels downstream through at least a portion of the compression region prior to combustion. A combustion region communicates with the compression region and is proximate to the periphery of the rotor. The air/fuel mixture flows from the compression region to the combustion region to undergo combustion in the combustion region. A power region communicates with the combustion region and includes an outlet proximate to the rotation axis of the rotor. The power region extends from the periphery of the rotor to the outlet. The air/fuel mixture exits the flow conduit through the outlet after combustion. The compression region, combustion region, and power region of the flow conduit define a substantially U-shaped flow path along which the air/fuel mixture travels during engine operation.
According to another preferred embodiment of the invention, the combined volume of the combustion region and the power region is substantially greater than the volume of the compression region.
According to another preferred embodiment of the invention, the rotor includes at least two separate flow conduits.
According to another preferred embodiment of the invention, the rotor includes at least two interconnected flow conduits having respective compression, combustion, and power regions. The flow conduits are interconnected such that at least one of the compression regions is configured to deliver the air/fuel mixture simultaneously to at least two of the combustion regions.
According to another preferred embodiment of the invention, an inducer is located at the inlet of the compression region.
According to another preferred embodiment of the invention, a fuel injector is located proximate to the inlet of the compression region to introduce fuel into the flow conduit.
According to another preferred embodiment of the invention, a spark plug is located proximate to the inlet of the compression region to ignite the air/fuel mixture.
According to another preferred embodiment of the invention, the outlet of the power region includes an outlet nozzle through which the air/fuel mixture exits the flow conduit after combustion.
According to another preferred embodiment of the invention, the outlet nozzle is constructed such that the combusted air/fuel mixture exits the flow conduit as an exhaust jet. The exhaust jet has a velocity vector including a component vector at right angles to the rotation axis of the rotor.
According to another preferred embodiment of the invention, a turbine is arranged downstream of the outlet nozzle for actuation by the combusted air/fuel mixture exiting the flow conduit.
According to another preferred embodiment of the invention, the turbine is operatively connected to a rotor shaft at the rotation axis of the rotor.
According to another preferred embodiment of the invention, the turbine includes first and second portions. The first portion delivers power directly to the rotor shaft and the second portion delivers power to a second shaft.
According to another preferred embodiment of the invention, a vacuum pump is connected to an interior of the engine housing for maintaining air surrounding the rotor at a pressure below atmospheric pressure during engine operation.
According to another preferred embodiment of the invention, an exterior surface of the rotor is contoured to minimize aerodynamic drag.
According to another preferred embodiment of the invention, interior walls of the housing adjacent to the exterior surface of the rotor are contoured to minimize aerodynamic drag.
According to another preferred embodiment of the invention, the distance between the exterior surface of the rotor and the interior surface of the housing is at least two times the boundary layer thickness of the air between the rotor and the housing.
According to another preferred embodiment of the invention, the compression region of the flow conduit comprises means for diffusing the fuel into the air to form an air/fuel mixture to enhance combustion.
According to another preferred embodiment of the invention, the engine housing defines an entrance port for directing incoming air to the inlet of the compression region.
According to another preferred embodiment of the invention, the compression region defines a fuel delivery opening between the inlet and the combustion region.
In another embodiment, the invention is a rotor mounted for rotation within a housing of a rotary internal combustion engine. The rotor is configured for rotation about an axis and includes at least one flow conduit. The at least one flow conduit includes a compression region having an inlet proximate to the rotation axis of the rotor and extending radially towards a periphery of the rotor. A mixture of air and fuel enters the flow conduit through the inlet and travels downstream through at least a portion of the compression region prior to combustion. A combustion region communicates with the compression region and is proximate to the periphery of the rotor. The air/fuel mixture flows from the compression region to the combustion region to undergo combustion in the combustion region. A power region communicates with the combustion region and includes an outlet proximate to the rotation axis of the rotor. The power region extends from the periphery of the rotor to the outlet. The air/fuel mixture exits the flow conduit through the outlet after combustion. The compression region, combustion region, and power region of the flow conduit define a substantially U-shaped flow path along which the air/fuel mixture travels during engine operation.